JP2022102990A - Acrylate photocurable resin composition containing bismaleimide compound and having improved mechanical properties and heat resistance - Google Patents

Abstract

To provide an acrylate photocurable resin composition containing bismaleimide compound and having improved mechanical properties and heat resistance.SOLUTION: A photocurable resin composition is obtained by adding, to a photocurable acrylate monomer, a bismaleimide compound composed of 2-methylpentane-1,5-bismaleimide and 1-maleimide-3-maleimidemethyl-3,5,5-trimethylcyclohexane.SELECTED DRAWING: None

Description

The present invention relates to an acrylate photocurable resin composition.

The method of curing a resin can be roughly divided into thermosetting and photocuring. Generally, in thermosetting, a thermosetting resin monomer and a composition (varnish) thereof are dissolved in a solvent and thermoset. The solvent is volatilized and removed during heating, but it is difficult to completely remove the solvent in the resin. There is also a problem that the bubbles generated in the volatilization process cannot be completely removed by the time they harden. Furthermore, the solvent itself is regarded as a safety and hygiene problem for workers, and research on solvent-free varnishes is also active.

On the other hand, in photo-curing, the photo-curable resin monomers and their compositions are irradiated with ultraviolet rays or the like to be photo-cured. The curing temperature is relatively low, such as at room temperature, and it is common to use solvent-free varnish. Examples of the resin monomer often used in photocuring include acrylate compounds.

Acrylate resin is widely used because it has excellent transparency, weather resistance, rigidity, etc. among plastics, and has high sensitivity to photoradical polymerization and high curing speed. In addition, a wide variety of acrylate monomers, which are raw materials for resins, are commercially available, and its characteristics can be controlled by selecting the number and structure of acrylate groups. For example, it is used in aquarium tanks and aircraft windows that require transparency, coating liquid crystal panels and the like by utilizing its high hardness, and paints for buildings by utilizing its excellent weather resistance. In recent years, it has also been used as a monomer for 3D printers for stereolithography, taking advantage of its high-speed curability.

However, the mechanical properties of the acrylate resin are not sufficient, and the cured resin obtained from the stereolithography acrylate monomer still has a problem in terms of heat resistance.

As a method for improving the heat resistance of the acrylate resin, there is an example in which a bismaleimide compound is added, but these studies are studies on a thermosetting system (Patent Document 1), and there are few studies on photocuring.

The reason is that the existing bismaleimide compound has poor solubility in the acrylate monomer and has an aromatic ring in the structure, so that it easily inhibits photocuring.

Therefore, there is a demand for a photocurable bismaleimide compound that is soluble in an acrylate monomer for photocuring.

JP-A-2018-172565

An object of the present invention is to provide an acrylate photocurable resin composition containing a bismaleimide compound and having improved mechanical properties and heat resistance.

Techniques for solving problems

In order to solve the above problems, a bismaleimide compound composed of Chemical formula 1 and Chemical formula 2 is added to a photocurable acrylate monomer to obtain a photocurable resin composition.

Effect of the invention

By carrying out the present invention, it is possible to obtain a photocurable acrylate resin having improved physical properties by bismaleimide.

Hereinafter, specific embodiments of the present invention will be described.

The bismaleimide compound used in the present invention is a bismaleimide compound represented by Chemical formula 1 (1-maleimide-3-maleimidemethyl-3,5,5-trimethylcyclohexane) and a bismaleimide compound represented by Chemical formula 2 (1-maleimide-3-maleimidemethyl-3,5,5-trimethylcyclohexane). It is limited to a mixture of 2-methylpentane-1,5-bismaleimide). It is desirable to mix these two types of bismaleimide compounds in the range of 0.2 to 0.8: 0.8 to 0.2, and further in the range of 0.4 to 0.6: 0.6 to 0.4. Is more desirable.

If the ratio deviates from this ratio, the bismaleimide compound dissolved in the acrylate is likely to precipitate, which affects the physical properties and appearance of the resin after curing. Further, the two types of bismaleimide compounds may be mixed in advance and then added to the acrylate, or each may be added directly.

The base acrylate monomer may be any one as long as it can be photocured. There is no limitation on the number of functional groups, and the acrylate compound is selected according to the required properties.

For example, a monomer composition is often selected by combining a monofunctional to polyfunctional monomer or an oligomer. For example, among polyfunctional acrylates, trifunctional acrylate has a high crosslink density and a high curing rate, and trimethylolpropane triacrylate (hereinafter referred to as trimethylolpropane triacrylate). Abbreviated as TMPTA: manufactured by Tokyo Kasei Kogyo Co., Ltd.) and PO-modified trimethylolpropane triacrylate (hereinafter abbreviated as TMP-3P: manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.).

On the other hand, when it is desired to reduce the viscosity of the resin, acrylate monomers having a small number of functional groups can be used, and they may also be used as a diluent. Generally, the viscosity of the monomer solution is lowered and the flexibility is reduced. However, if the amount added is too large, the elastic modulus is lowered. Therefore, it is desirable to select a compound having a high dilution effect and an excellent curing rate.

More specifically, acryloyl morpholine (hereinafter abbreviated as ACMO: manufactured by Tokyo Chemical Industry Co., Ltd.) and 2- (2-vinyloxyethoxy) ethyl acrylate (hereinafter abbreviated as VEEA: manufactured by Nippon Shokubai Co., Ltd.) are desirable and diluted. The amount of the agent added does not depend on the amount added as long as it can be cured and the deterioration of physical properties is allowed.

The photo-curing method, that is, the ultraviolet curing method may be a general method. The light source includes, for example, a metal halide lamp, a high-pressure mercury lamp, a xenon lamp, or the like, and any lamp that can irradiate a wavelength at which the resin can be cured may be used.

The irradiation wavelength of the light source is not specified as long as it can cure the resin, but it may be in the wavelength range of 250 to 600 nm, and particularly preferably in the range of 300 to 450 nm.

Although the present invention requires a photo-curing initiator, it may be selected depending on the light source for curing. For example, since metal halide lamps and xenon lamps have a wide wavelength range, acetophenone type and benzophenone type, which are general photocuring initiators, can be used. Further, even when a UV-LED lamp light source is used, a photocuring initiator corresponding to the wavelength may be used. For example, a phosphine-based initiator can be photocured even at a long wavelength of 400 nm or more.

Although the sensitizer is not particularly required in the present invention, it may be appropriately added when it is desired to further increase the curing rate.

In addition, any compound that is compatible with the acrylate-bismaleimide composition and does not inhibit photocuring may be added as appropriate.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto. The composition and test results used in the test are shown in Table 1.

As the composition for photo-curing, each acrylate monomer of the base was stirred and mixed at 80 ° C., and then a photo-curing initiator was added at room temperature to prepare a comparative example composition.

On the other hand, each acrylate monomer based at 80 ° C. and the bismaleimide compounds of Chemical formula 1 and Chemical formula 2 were melt-stirred and mixed, and a photocuring initiator was added at room temperature to obtain an example composition.

Examples 1 and 2 are formulations in which 15% of each of the bismaleimide mixture is added to the acrylate monomer mixed at an arbitrary ratio. Example 1 is a composition when TMPTA is used as a trifunctional acrylate monomer, and Example 2 is a case where TMPTA is changed to PO-modified TMP-3P.

〔Glass-transition temperature〕
In Example 2 and Comparative Example 2, which are PO-modified TMPTA (TMP-3P) systems, the glass transition temperature was measured by a viscoelasticity measuring device. According to it, the addition of bismaleimide (Example 2) increased the glass transition temperature by about 25 ° C. as compared with Comparative Example 2.

[Tension modulus and tensile strength at break]
As a result of conducting a tensile test of each formulation, the tensile breaking strength was higher in Examples 1 and 2 of the bismaleimide-added system than in Comparative Examples 1 and 2 of the additive-free system.
On the other hand, the tensile fracture rate is the same in all the formulations, and it can be seen that bismaleimide does not adversely affect the acrylate resin in the minute deformation region.

In this way, according to the present invention, a photocurable acrylate resin composition having improved physical properties by bismaleimide can be obtained.

Claims (4)

A resin composition containing a bismaleimide compound composed of Chemical formula 1 and Chemical formula 2 into a photocurable acrylate monomer.

A cured product comprising a resin composition containing a bismaleimide compound comprising the chemical formulas 1 and 2 of claim 1 into a photocurable acrylate monomer. A resin adjusted so that the mixed molar ratio of the compound represented by Chemical formula 1 and the compound represented by Chemical formula 2 of claim 1 is in the range of 0.3: 0.7 to 0.7: 0.3. Composition. A resin composition adjusted so that the total weight of the compound represented by Chemical formula 1 and the compound represented by Chemical formula 2 of claim 1 is within the range of 5 to 20% of the total weight of the composition.